Shaping the Trunk Road Network, a consultation paper published by the then Scottish Office Transport Minister in 1994, identified the following criteria for determining a trunk road:provide the road user with a coherent and continuous system of routes which serve destinations of importance to industry, commerce, agriculture and tourism;define nationally important routes which will be developed in line with strategic national transport demands; andensure that these roads which are of predominantly local importance are managed locally.Neither these criteria nor the network established from 1 April 1996, following the consultation, have been reviewed subsequently.